Articulation mechanism for surgical stapling device

ABSTRACT

A surgical device includes an elongate body, a tool assembly, a drive assembly, and an articulation mechanism for moving the tool assembly between a non-articulated position and articulated positions. The articulation mechanism includes an articulation link, a first pivot link that is positioned on a first side of a flexible beam, and a second pivot link positioned on a second side of the flexible beam. The first and second pivot links are configured to control the path of movement of the flexible beam of the drive assembly as the flexible beam is moved between its retracted and advanced positions in non-articulated and articulated positions of the tool assembly to maintain a predetermined distance of movement of the clamp member within the tool assembly constant.

FIELD

This technology is generally related to surgical devices for endoscopicuse and, more specifically, to surgical devices including articulationmechanisms for articulating tool assemblies.

BACKGROUND

Various types of surgical devices used to endoscopically treat tissueare known in the art, and are commonly used, for example, for closure oftissue or organs in transection, resection, and anastomoses procedures,for occlusion of organs in thoracic and abdominal procedures, and forelectrosurgically fusing or sealing tissue.

One example of such a surgical device is a surgical stapling device.Surgical stapling devices include a tool assembly having an anvilassembly and a cartridge assembly, and a drive assembly that is movablethrough the tool assembly. Typically, the drive assembly includes aflexible drive beam and a clamp member that is supported on a distal endof the flexible drive beam. The drive assembly is movable to advance theclamp member through the tool assembly to approximate the cartridge andanvil assemblies and to advance an actuation sled through the cartridgeassembly to eject staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to asurgical site is achieved through a small incision or through a narrowcannula inserted through a small entrance wounds in a patient. Becauseof limited area available to access the surgical site, many endoscopicdevices include mechanisms for articulating the tool assembly of thedevice about a pivot axis in relation to a body portion of the device.When the tool assembly is in an articulated position and the drive beamis advanced to actuate the tool assembly, the drive beam bends about thepivot axis as the drive assembly is advanced to advance the clamp memberthrough the tool assembly. This bending of the drive beam in relation tothe pivot axis causes the drive beam to move to a position off the pivotaxis and changes a stroke length of the drive beam required to fullyactuate the tool assembly. This change in stroke length increasesexponentially as the tool assembly is articulated over a greater angleand may adversely affect operation of the stapling device.

A continuing need exists in the art for an articulating mechanism for asurgical device that can maintain distance of advancement of a clampmember within a tool assembly constant in both non-articulated andarticulated positions of the tool assembly.

SUMMARY

Aspects of this disclosure are directed to a surgical device having anelongate body, a tool assembly, a drive assembly, and an articulationmechanism for moving the tool assembly between a non-articulatedposition and articulated positions. The drive assembly includes aflexible beam and a clamp member that is supported on the flexible beam.The drive assembly is movable through a predetermined stroke to move theclamp member a predetermined distance through the tool assembly toactuate the tool assembly. The articulation mechanism includes anarticulation link, a first pivot link that is positioned on a first sideof the flexible beam and a second pivot link positioned on a second sideof the flexible beam. The first pivot link has a convex guide surfacethat is engaged with the first side of the flexible beam and the secondpivot link has a convex guide surface that is engaged with the secondside of the flexible beam. The convex and concave guide surfaces areconfigured to control the path of movement of the flexible beam as theflexible beam is moved between its retracted and advanced positions inthe non-articulated and articulated positions of the tool assembly tomaintain the predetermined distance of movement of the clamp memberwithin the tool assembly constant.

Aspects of this disclosure are directed to a surgical device thatincludes an elongate body, a tool assembly, a drive assembly, and anarticulation mechanism. The elongate body defines a longitudinal axisand has a proximal portion a distal portion. The tool assembly ispivotably coupled to the distal portion of the elongate body and definesa longitudinal axis. The tool assembly is pivotable between anon-articulated position in which the longitudinal axis of the toolassembly is aligned with the longitudinal axis of the elongate body andarticulated positions in which the longitudinal axis of the toolassembly is misaligned with the longitudinal axis of the elongate body.The drive assembly includes a flexible drive beam and a clamp member.The flexible drive beam has a proximal portion, a distal portion, afirst side, and a second side. The distal portion supports the clampmember. The drive assembly is movable through a predetermined strokelength to move the clamp member within the tool assembly a predetermineddistance. The articulation assembly includes an articulation link andfirst and second pivot links. The articulation link has a proximalportion and a distal portion. The first pivot link is positionedadjacent the first side of the flexible drive beam and has a proximalportion that is pivotably coupled to the distal portion of thearticulation link and a distal portion that is pivotably coupled to thetool assembly. The second pivot link is positioned adjacent the secondside of the flexible drive beam and has a distal portion that is coupledto the tool assembly. The first and second pivot links are configured tocontrol a path of movement of the flexible beam as the flexible beam ismoved between its retracted and advanced positions to maintain thepredetermined distance of movement of the clamp member within the toolassembly constant in the non-articulated and articulated positions ofthe tool assembly.

In aspects of the disclosure, the first pivot link includes a convexguide surface that is engaged with the first side of the flexible drivebeam to define a deformed portion in the flexible beam.

In some aspects of the disclosure, the second pivot link includes aconcave guide surface that faces the second side of the flexible drivebeam.

In certain aspects of the disclosure, the tool assembly is pivotablycoupled to the distal portion of the elongate body about a pivot axisthat is laterally offset from the longitudinal axis of the toolassembly.

In aspects of the disclosure, the second pivot link includes a proximalend that is in abutting relation to the distal portion of the elongatebody.

In some aspects of the disclosure, the surgical device includes aretaining member that is secured to the elongate body adjacent thesecond pivot link to obstruct outward movement of the second pivot link.

In certain aspects of the disclosure, the tool assembly includes ananvil and a cartridge assembly that are pivotably coupled together suchthat the tool assembly is movable between open and clamped positions.

In aspects of the disclosure, the articulation link is positioned on thefirst side of the flexible drive beam.

In some aspects of the disclosure, the surgical device includes astabilizing member that is positioned on each side of the flexible drivebeam, and each of the stabilizing members extends from a positionproximal of the pivot axis to a position distal of the pivot axis.

In certain aspects of the disclosure, each of the stabilizing membersdefines a centrally located concavity.

In aspects of the disclosure, each of the stabilizing members includes aproximal portion that is slidably engaged with the elongate body.

In some aspects of the disclosure, the surgical device includes a handleassembly that is coupled to the proximal portion of the elongate body.

In certain aspects of the disclosure, the tool assembly forms part of areload assembly that includes a proximal body portion and the toolassembly.

In aspects of the disclosure, the proximal body portion has a proximalportion that is releasably coupled to the elongate body.

Other aspects of the disclosure are directed to a reload assembly thatincludes a proximal body portion, a tool assembly, a drive assembly, andan articulation mechanism. The proximal body portion defines alongitudinal axis and has a proximal portion and a distal portion. Thetool assembly is pivotably coupled to the distal portion of the proximalbody portion and defines a longitudinal axis. The tool assembly ispivotable between a non-articulated position in which the longitudinalaxis of the tool assembly is aligned with the longitudinal axis of theproximal body portion and articulated positions in which thelongitudinal axis of the tool assembly is misaligned with thelongitudinal axis of the proximal body portion. The tool assemblyincludes an anvil and a cartridge assembly that are pivotable inrelation to each other between open and clamped positions. The driveassembly includes a flexible drive beam and a clamp member. The flexibledrive beam has a proximal portion, a distal portion, a first side, and asecond side. The distal portion supports the clamp member. The driveassembly is movable through a predetermined stroke length to move theclamp member within the tool assembly a predetermined distance. Thearticulation assembly includes an articulation link and first and secondpivot links. The articulation link has a proximal portion and a distalportion. The first pivot link is positioned adjacent the first side ofthe flexible drive beam and has a proximal portion that is pivotablycoupled to the distal portion of the articulation link and a distalportion that is pivotably coupled to the tool assembly. The second pivotlink is positioned adjacent the second side of the flexible drive beamand has a distal portion that is coupled to the tool assembly. The firstand second pivot links are configured to control a path of movement ofthe flexible beam as the flexible beam is moved between its retractedand advanced positions to maintain the predetermined distance ofmovement of the clamp member within the tool assembly constant in thenon-articulated and articulated positions of the tool assembly.

Other features of the disclosure will be appreciated from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure are described herein below withreference to the drawings, wherein:

FIG. 1 is a side perspective view of a powered version of a surgicaldevice including an articulation mechanism according to aspects of thedisclosure with a tool assembly of the stapling device in anon-articulated position;

FIG. 2 is a side perspective view of a manual version of a surgicaldevice including the articulation mechanism according to aspects of thedisclosure with the tool assembly of the stapling device in anarticulated position;

FIG. 3 is an exploded, side perspective view of a proximal body portion,a mounting assembly, and pivot links of a reload assembly of thesurgical device shown in FIGS. 1 and 2 ;

FIG. 3A is a side perspective view of pivot plates and retaining memberof the reload assembly shown in FIG. 3 ;

FIG. 4 is an exploded, side perspective view of the mounting assemblyand pivot links of the reload assembly shown in FIG. 3 ;

FIG. 5 is a side perspective view of the assembled mounting assembly andpivot links shown in FIG. 4 ;

FIG. 6 is a side perspective view of the distal portion of the reloadassembly shown in FIG. 3 with an outer tube of the proximal body portionshown in phantom and the tool assembly in a non-articulated position;

FIG. 7 is a side perspective view of the distal portion of the reloadassembly shown in FIG. 6 with the anvil assembly removed and a halfsection of the housing of the proximal body portion and the outer tuberemoved with the tool assembly in a non-articulated position;

FIG. 8 is a top view of the distal portion of the reload assembly shownin FIG. 6 with a drive assembly of the reload assembly shown in phantomand the tool assembly in a non-articulated position;

FIG. 9 is an enlarged view of the indicated area of detail shown in FIG.8 ;

FIG. 10 is a cross-sectional view taken along section line 10-10 of FIG.8 ;

FIG. 11 is a cross-sectional view taken along section line 11-11 of FIG.8 ;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG.9 ;

FIG. 13 is a top view of a central portion of the reload assembly shownin FIG. 8 with the tool assembly in the articulated position;

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG.13 with the tool assembly in a first articulated position; and

FIG. 15 is a cross-sectional view through the central portion of thereload assembly shown in FIG. 13 with the tool assembly in a secondarticulated position.

DETAILED DESCRIPTION

The disclosed surgical device will now be described in detail withreference to the drawings in which like reference numerals designateidentical or corresponding elements in each of the several views.However, it is to be understood that aspects of the disclosure aremerely exemplary of the disclosure and may be embodied in various forms.Well-known functions or constructions are not described in detail toavoid obscuring the disclosure in unnecessary detail. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the disclosure in virtually any appropriately detailed structure.

In this description, the term “proximal” is used generally to refer tothat portion of the device that is closer to a clinician, while the term“distal” is used generally to refer to that portion of the device thatis farther from the clinician. In addition, the term “endoscopic” isused generally to refer to endoscopic, laparoscopic, arthroscopic,and/or any other procedure conducted through a small diameter incisionor cannula, and the term “clinician” is used generally to refer tomedical personnel including doctors, nurses, and support personnel.Further, directional terms such as “front”, “rear”, “upper”, “lower”,“top”, “bottom”, and similar terms are used to assist in understandingthe description and are not intended to limit the disclosure.

The disclosed surgical device includes a body portion and a toolassembly that is coupled to the body portion by a pivot member tofacilitate articulation of the tool assembly in relation to the bodyportion. The body portion includes an articulation mechanism and a driveassembly. The drive assembly has a resilient drive beam and a clampmember that is positioned within the tool assembly. The drive assemblyis movable between retracted and advanced positions over a predeterminedstroke to advance the clamp member within the tool assembly apredetermined distance to move the tool assembly from an open positionto a clamped position and to eject staples from the tool assembly. Thearticulation mechanism includes pivot links that engage the driveassembly as the drive assembly moves through the predetermined stroke tocontrol the path of movement of the drive assembly and maintain thepredetermined distance of movement of the clamp member within the toolassembly constant in the non-articulated and articulated positions ofthe tool assembly.

FIG. 1 illustrates a surgical device according to aspects of thedisclosure shown generally as surgical device 10. The surgical device 10includes a handle assembly 12, an elongate body 14, and a tool assembly16. The elongate body 14 defines a central longitudinal axis “X” (FIG. 1) and the tool assembly 16 defines a longitudinal axis “Y” (FIG. 13 ).The tool assembly 16 is pivotally coupled to the elongate body 14 andcan pivot between a non-articulated position (FIG. 1 ) in which thelongitudinal axes “X” and “Y” of the elongate body 14 and tool assembly16 are aligned with each other to articulated positions in which thelongitudinal axes “X” and “Y” of the elongate body 14 and tool assembly16 are misaligned with each other (FIG. 13 ).

The handle assembly 12 includes a body 12 a that defines a stationaryhandle 18 and includes actuation buttons 20 that are operable toinitiate operation of the surgical device 10, i.e., approximation of thetool assembly 16, articulation of the tool assembly 16, and firing ofstaples from the tool assembly 16. In aspects of the disclosure, thehandle assembly 12 supports a rotation knob 22 that is coupled to aproximal portion 14 a of the elongate body 14 and is rotatable to rotatethe elongate body 14 and the tool assembly 16 in relation to the handleassembly 12 about the longitudinal axis “X”. While the surgical device10 may be configured to fire staples, it is contemplated that thesurgical device 10 may be adapted to fire any other suitable fastenerssuch as clips and two-part fasteners. Although the surgical device 10 isillustrated as a surgical stapling device 10, it is also envisioned thatcertain components described herein may be adapted for use in othertypes of articulating endoscopic surgical instruments includingendoscopic forceps, graspers, dissectors, other types of surgicalstapling instruments, powered vessel sealing devices and/or cuttingdevices.

Although FIG. 1 illustrates the stapling device 10 as including apowered handle assembly 12, it is envisioned that the stapling device10′ can include a handle assembly 12′ that is manually actuated such asillustrated in FIG. 2 . The manually actuated handle assembly 12′supports the elongate body 14 and the tool assembly 16 and includes abody 12 a′ that defines a stationary handle 18′. The handle assembly 12′includes a pivotable trigger 20′ that is movable in relation to thestationary handle 18′ to actuate the tool assembly 16. The stationaryhandle 12′ supports a rotation knob 22′ that is engaged with theelongate body 14 such that rotation of the rotation knob 22′ causesrotation of the elongate body 14 and the tool assembly 16 in relation tothe handle assembly 12′. The stapling device 10′ also supports anarticulation lever 24′ that is rotatable to articulate the tool assembly16.

In aspects of the disclosure, the tool assembly 16 forms part of areload assembly 40 that is releasably coupled to the elongate body 14and includes a proximal body portion 42, the tool assembly 16, and amounting assembly 44 that pivotably couples the tool assembly 16 to thedistal portion of the proximal body portion 42. The proximal bodyportion 42 is coaxial with the longitudinal axis “X” of the elongatebody 14 and has a proximal portion 42 a that is releasably coupled to adistal portion 14 a of the elongate body 14. It is envisioned that thetool assembly 16 can be pivotably secured to the elongate body 14 viathe mounting assembly 44 and need not form part of a reload assembly.

FIGS. 1-3 illustrate the tool assembly 16 which includes an anvil 50 anda cartridge assembly 52. The anvil 50 is coupled to the cartridgeassembly 52 by pivot members 54 (FIG. 3 ) that facilitate movement ofthe anvil 50 in relation to the cartridge assembly 52 between open andclamped positions. The cartridge assembly 52 includes a channel member56 and a staple cartridge 58. The channel member 56 defines a cavity 56a that receives the staple cartridge 58. In aspects of the disclosure,the staple cartridge 58 is releasably received within the channel member56 and can be replaced to facilitate reuse of the stapling device 10(FIGS. 1 and 2 ). Alternately, it is envisioned that the staplecartridge 58 can be fixedly retained within the channel member 56 andthe entire reload assembly can be replaced to facilitate reuse of thestapling device 10. Although the cartridge assembly 52 is shown to pivottowards the anvil 50, it is envisioned that the cartridge assembly 52could be stationary and the anvil 50 could pivot towards the cartridgeassembly 52.

FIG. 3 illustrates an exploded view of the reload assembly 40 whichincludes the proximal body portion 42, the mounting assembly 44 (FIG. 1), and the tool assembly 16. The mounting assembly 44 includes a firstmounting member 60 and a second mounting member 62 that are securedtogether with screws or rivets 64 to define an enclosed channel 66between the first and second mounting members 60 and 62, respectively.The second mounting member 62 defines threaded bores 68. The channelmember 56 of the cartridge assembly 52 includes a proximal portion thatdefines bores 70 that receive the pivot members 54. The pivot members 54extend through the bores 70 in the proximal portion of the channelmember 56 and into the threaded bores 68 of the second mounting member62 to pivotably secure the cartridge assembly 52 to the mountingassembly 44. The pivot members 54 also extend through openings 72 in aproximal portion of the anvil 50 to secure the anvil 50 to the mountingassembly 44. The proximal portion of the anvil 50 defines cutouts 74through which the rivets 64 pass to fixedly secure the anvil 50 to themounting assembly 44.

The proximal body portion 42 of the reload assembly 40 includes ahousing 80 (FIG. 6 ), a drive assembly 82, and an articulation mechanism84 (FIG. 7 ). The housing 80 is formed from first and secondhalf-sections 80 a and 80 b that are secured together to define internalchannels that facilitate longitudinal movement of the drive assembly 82and the articulation mechanism 84 within the housing 80. Each of thehousing half-sections 80 a and 80 b includes a distal portion thatdefines a stepped cutout 86 (only one is shown). The first half-section80 a includes a proximal portion 88 that is adapted to be releasablycoupled to the distal portion of the elongate body 14 (FIG. 2 ). U.S.Pat. No. 8,132,706 (hereinafter “the '706 Patent”) discloses a reloadassembly having a proximal body portion including a housing that isadapted to releasably engage a body portion of a surgical staplingdevice suitable for use with the disclosed surgical device.

FIGS. 3-5 illustrate the mounting assembly 44 which as described aboveincludes mounting members 60 and 62 that are secured together withrivets 64. Each of the mounting members 60 and 62 includes a proximalportion that includes or defines a pivot member 90 (only one is shown).The pivot members 90 are coaxial and define an articulation axis “Z”(FIG. 2 ) about which the tool assembly 16 articulates. The articulationaxis “Z” is spaced laterally of the central longitudinal axis “X” of theelongate body portion 14 (FIG. 2 ) and the proximal body portion 42 ofthe reload assembly 40. The mounting assembly 44 also includes first andsecond pivot plates 92 a and 92 b. Each of the pivot plates 92 a and 92b includes a body having a stepped configuration that corresponds to theconfiguration of one of the stepped cutouts 86 formed in the housinghalf-sections 80 a and 80 b. Each of the pivot plates 92 a and 92 b alsoincludes a distal portion that defines a bore 94 that receives one ofthe pivot members 90 of the mounting members 60 and 62. The bodies ofthe pivot plates 92 a and 92 b are received in the respective steppedcutouts 86 of the housing half-sections 80 a and 80 b and the pivotmembers 90 of the first and second mounting members 60 and 62 arereceived within the respective bores 94 of the pivot plates 92 a and 92b to pivotably secure the mounting assembly 44 and tool assembly 16 tothe proximal body portion 42 of the reload assembly 40 about thearticulation axis “Z”.

The articulation mechanism 84 (FIG. 7 ) of the reload assembly 40includes an articulation link 100 and first and second pivot links 102and 104. The articulation link 100 has a proximal portion and a distalportion. The proximal portion is adapted to engage an articulation drivemember (not shown) within the elongate body 14 (FIG. 2 ) when the reloadassembly 40 (FIG. 2 ) is coupled to the elongate body 14. In aspects ofthe disclosure, the proximal portion of the articulation link 100includes a transverse portion 106 that is adapted to engage thearticulation drive member (not shown) within the elongate body 14. Thedistal portion of the articulation link 100 defines a through bore 108that is pivotably coupled to the first pivot link 102 as described infurther detail below. The articulation link 100 is supported within achannel defined within the housing 80 (FIG. 6 ) of the proximal bodyportion 42 for longitudinal movement between retracted and advancedpositions.

FIGS. 4 and 5 illustrate the first pivot link 102 which includes a body110 (FIG. 4 ) having a curved configuration and proximal and distalpivot members 112 and 114. The proximal pivot member 112 is receivedwithin the through bore 108 in the distal portion of the articulationlink 100 to pivotably couple the first pivot link 102 to the distalportion of the articulation link 100. The distal pivot member 114 of thefirst pivot link 102 is pivotably received between the first and secondmounting members 60 and 62 to pivotably couple the first pivot link 102to the mounting assembly 44 (FIG. 6 ). The body 110 of the first pivotlink 102 includes a convex guide surface 116 that faces the second pivotlink 104 and extends inwardly across the longitudinal axis “X” (FIG. 12) of the elongate body 14 and proximal body portion 42.

The second pivot link 104 includes a body 120 that includes a distalpivot member 122 and a proximal abutment member 124. The distal pivotmember 122 of the second pivot link 104 is received between the firstand second mounting members 60 and 62 to pivotably couple the secondpivot link 104 to the mounting assembly 44 (FIG. 6 ). The abutmentmember 124 is engaged with a wall 126 on the distal portion of thehousing half-section 80 b (FIG. 3 ). The pivot link 104 includes aconcave guide surface 132 that faces the convex guide surface 116 of thefirst pivot link 102.

A retaining member 130 (FIG. 3A) has a C-shaped body and is secured tothe pivot plates 92 a and 92 b outwardly of the pivot link 104 to limitoutward pivotable movement of the pivot link 104 (FIG. 3A). In aspectsof the disclosure, ends of the C-shaped body of the retaining member 130are welded to the pivot plates 92 a and 92 b to secure the retainingmember 130 outwardly of the pivot link 104.

FIG. 3 illustrates the drive assembly 82 which includes a flexible drivebeam 140 and a clamp member 42. The flexible drive beam 140 has aproximal portion and a distal portion. The proximal portion of the drivebeam 140 is coupled to a control rod (not shown) within the elongatebody 14 (FIG. 2 ) and is movable in response to movement of the controlrod between retracted and advanced positions. In aspects of thedisclosure, the flexible drive beam 140 is formed from stacked sheets ofmaterial and can bend about the articulation axis “Z” (FIG. 2 ) when thetool assembly 16 is in an articulated position and the surgical device10 is fired. The clamp member 142 of the drive assembly 82 is secured tothe distal portion of the drive beam 140 and is movable through the toolassembly 16 when the flexible drive beam 140 is moved between itsretracted and advanced positions to actuate the tool assembly 16. Inaspects of the disclosure, the clamp member 142 of the drive assembly 82has an I-beam configuration and supports a knife blade 142 a. For adetailed description of the construction and operation of the driveassembly 82, see the '706 Patent.

The reload assembly 40 includes a flexible stabilizing member 150 and152 positioned on each side of the flexible drive beam 140. Each of theflexible stabilizing members 150 and 152 extends from the proximal bodyportion 42 through the channel 66 defined by the mounting assembly 44and has a distal end fixedly coupled to the tool assembly 16 and aproximal end received within the housing 44 of the reload assembly 40for sliding movement. The stabilizing member 150 defines a centrallylocated concavity 150 a that receives the convex guide surface 116 ofthe first pivot member 102 and the stabilizing member 152 defines acentrally located convexity 152 a that is received within the concaveguide surface 132 of the pivot link 104.

In some aspects of the disclosure, the disclosed tool assembly 16 of thereload assembly 40 articulates in a single direction over a range ofarticulation of about 90 degrees in a direction towards the pivot link102. FIGS. 6-12 illustrate the reload assembly 40 with the tool assembly16 in a non-articulated position. In the non-articulated position, theflexible drive beam 140 of the drive assembly 82 is spaced laterally ofthe articulation axis “Z” (FIG. 2 ) and the longitudinal axis “X” alongits length in a direction towards the second pivot link 104 and isengaged by the stabilizing member 150 in the area adjacent the convexguide surface 116 of the first pivot link 102. The configuration of theconvex guide surface 116 of the first pivot link 102 deforms theflexible drive beam 140 a to define a deformed portion 140 a of theflexible drive beam 140 which is spaced further outwardly of thelongitudinal axis “X” of the proximal body portion 42 and of thearticulation axis “Z” than the proximal and distal portions of theflexible drive beam 140. The deformed portion 140 a shortens theeffective longitudinal length of the drive beam 140 to provide theappropriate stroke length to advance the clamp member 142 apredetermined distance within the tool assembly 16 to properly actuatethe tool assembly 16.

FIGS. 13 and 14 illustrate the reload assembly 40 of the surgical device10 (FIG. 2 ) with the tool assembly 16 in a first articulated position(approximately 30 degrees). In order to articulate the tool assembly 16of the reload assembly 40, the articulation link 100 is retracted in thedirection of arrow “A” to retract the first pivot link 102 and pivot thetool assembly 16 in the direction of arrow “B” in FIG. 14 about thearticulation axis “Z” (FIG. 2 ) defined by the pivot members 90 to theside of the flexible drive beam 140 that supports the first pivot link102. As illustrated, the deformed portion 140 a of the flexible drivebeam 140 becomes less pronounced as the tool assembly 16 is articulatedto adjust the effective longitudinal length of the flexible drive beam140 to move the clamp member 142 a a predetermined distance within thetool assembly 16 to properly actuate the tool assembly 16. Asillustrated, as the tool assembly 16 is articulated, the flexible drivebeam 140 moves inwardly to a position closer to the pivot axis “Z” (FIG.2 ) defined by the pivot members 90.

FIG. 15 illustrates the reload assembly 40 of the surgical device 10(FIG. 2 ) with the tool assembly 16 in a second articulated position(approximately 90 degrees). As illustrated, as the tool assembly 16 isarticulated about the pivot axis “Z” (FIG. 2 ) defined by the pivotmembers 90, the deformed portion 140 a of the flexible drive beam 140 isdiminished such that the effective longitudinal length of the flexibledrive beam 140 is maximized to move the clamp member 142 a thepredetermined distance within the tool assembly 16 to properly actuatethe tool assembly 16.

As summarized above, the configuration of the convex and concave guidesurfaces 116 and 132 of the first and second pivot links 102 and 104,respectively, controls the path of movement of the flexible drive beam140 in relation to the pivot axis “Z” to ensure that the clamp member142 moves the predetermined distance within the tool assembly 16 toproperly actuate the tool assembly 16.

Persons skilled in the art will understand that the devices and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary aspects of the disclosure. It isenvisioned that the elements and features illustrated or described inconnection with one exemplary embodiment may be combined with theelements and features of another without departing from the scope of thepresent disclosure. As well, one skilled in the art will appreciatefurther features and advantages of the disclosure based on theabove-described aspects of the disclosure. Accordingly, the disclosureis not to be limited by what has been particularly shown and described,except as indicated by the appended claims.

What is claimed is:
 1. A surgical device comprising: an elongate bodydefining a longitudinal axis, the elongate body having a proximalportion and a distal portion; a tool assembly pivotably coupled to thedistal portion of the elongate body, the tool assembly defining alongitudinal axis and pivotable between a non-articulated position inwhich the longitudinal axis of the tool assembly is aligned with thelongitudinal axis of the elongate body and articulated positions inwhich the longitudinal axis of the tool assembly is misaligned with thelongitudinal axis of the elongate body; a drive assembly including aflexible drive beam and a clamp member, the flexible drive beam having aproximal portion, a distal portion, a first side, and a second side, thedistal portion supporting the clamp member, the drive assembly beingmovable through a predetermined stroke length to move the clamp memberwithin the tool assembly a predetermined distance; and an articulationassembly including an articulation link and first and second pivotlinks, the articulation link having a proximal portion and a distalportion, the first pivot link positioned adjacent the first side of theflexible drive beam and having a proximal portion pivotably coupled tothe distal portion of the articulation link and a distal portionpivotably coupled to the tool assembly, the second pivot link positionedadjacent the second side of the flexible drive beam and having a distalportion coupled to the tool assembly, the first and second pivot linksbeing engaged with the flexible beam to control a path of movement ofthe flexible beam as the flexible beam is moved between its retractedand advanced positions to maintain the predetermined distance ofmovement of the clamp member within the tool assembly constant in thenon-articulated and articulated positions of the tool assembly; whereinthe first pivot link includes a convex guide surface that is engagedwith the first side of the flexible drive beam when the tool assembly isin the non-articulated position to define a deformed portion in theflexible drive beam.
 2. The surgical device of claim 1, wherein thesecond pivot link includes a concave guide surface that faces the secondside of the flexible drive beam.
 3. A surgical device comprising: anelongate body defining a longitudinal axis, the elongate body having aproximal portion and a distal portion; a tool assembly pivotably coupledto the distal portion of the elongate body, the tool assembly defining alongitudinal axis and pivotable between a non-articulated position inwhich the longitudinal axis of the tool assembly is aligned with thelongitudinal axis of the elongate body and articulated positions inwhich the longitudinal axis of the tool assembly is misaligned with thelongitudinal axis of the elongate body; a drive assembly including aflexible drive beam and a clamp member, the flexible drive beam having aproximal portion, a distal portion, a first side, and a second side, thedistal portion supporting the clamp member, the drive assembly beingmovable through a predetermined stroke length to move the clamp memberwithin the tool assembly a predetermined distance; and an articulationassembly including an articulation link and first and second pivotlinks, the articulation link having a proximal portion and a distalportion, the first pivot link positioned adjacent the first side of theflexible drive beam and having a proximal portion pivotably coupled tothe distal portion of the articulation link and a distal portionpivotably coupled to the tool assembly, the second pivot link positionedadjacent the second side of the flexible drive beam and having a distalportion coupled to the tool assembly, the first and second pivot linksbeing engaged with the flexible beam to control a path of movement ofthe flexible beam as the flexible beam is moved between its retractedand advanced positions to maintain the predetermined distance ofmovement of the clamp member within the tool assembly constant in thenon-articulated and articulated positions of the tool assembly; whereinthe tool assembly is pivotably coupled to the distal portion of theelongate body about a pivot axis, the pivot axis being laterally offsetfrom the longitudinal axis of the tool assembly.
 4. A surgical devicecomprising: an elongate body defining a longitudinal axis, the elongatebody having a proximal portion and a distal portion; a tool assemblypivotably coupled to the distal portion of the elongate body, the toolassembly defining a longitudinal axis and pivotable between anon-articulated position in which the longitudinal axis of the toolassembly is aligned with the longitudinal axis of the elongate body andarticulated positions in which the longitudinal axis of the toolassembly is misaligned with the longitudinal axis of the elongate body;a drive assembly including a flexible drive beam and a clamp member, theflexible drive beam having a proximal portion, a distal portion, a firstside, and a second side, the distal portion supporting the clamp member,the drive assembly being movable through a predetermined stroke lengthto move the clamp member within the tool assembly a predetermineddistance; an articulation assembly including an articulation link andfirst and second pivot links, the articulation link having a proximalportion and a distal portion, the first pivot link positioned adjacentthe first side of the flexible drive beam and having a proximal portionpivotably coupled to the distal portion of the articulation link and adistal portion pivotably coupled to the tool assembly, the second pivotlink positioned adjacent the second side of the flexible drive beam andhaving a distal portion coupled to the tool assembly, the first andsecond pivot links being engaged with the flexible beam to control apath of movement of the flexible beam as the flexible beam is movedbetween its retracted and advanced positions to maintain thepredetermined distance of movement of the clamp member within the toolassembly constant in the non-articulated and articulated positions ofthe tool assembly; and a stabilizing member positioned on each side ofthe flexible drive beam, each of the stabilizing members extending froma position proximal of the pivot axis to a position distal of the pivotaxis; wherein each of the stabilizing members defines a centrallylocated concavity.
 5. The surgical device of claim 4, wherein each ofthe stabilizing members includes a proximal portion that is slidablyengaged with the elongate body.
 6. A reload assembly comprising; aproximal body portion defining a longitudinal axis and having a proximalportion and a distal portion; a tool assembly pivotably coupled to thedistal portion of the proximal body portion, the tool assembly defininga longitudinal axis and being pivotable between a non-articulatedposition in which the longitudinal axis of the tool assembly is alignedwith the longitudinal axis of the proximal body portion and articulatedpositions in which the longitudinal axis of the tool assembly ismisaligned with the longitudinal axis of the proximal body portion, thetool assembly including an anvil and a cartridge assembly, the anvil andcartridge assembly pivotable in relation to each other between open andclamped positions; a drive assembly including a flexible drive beam anda clamp member, the flexible drive beam having a proximal portion, adistal portion, a first side, and a second side, the distal portionsupporting the clamp member, the drive assembly being movable through apredetermined stroke length to move the clamp member within the toolassembly a predetermined distance; and an articulation assemblyincluding an articulation link and first and second pivot links, thearticulation link having a proximal portion and a distal portion, thefirst pivot link positioned adjacent the first side of the flexibledrive beam and having a proximal portion pivotably coupled to the distalportion of the articulation link and a distal portion pivotably coupledto the tool assembly, the second pivot link positioned adjacent thesecond side of the flexible drive beam and having a distal portioncoupled to the tool assembly, the first and second pivot links beingengaged with the flexible beam to control a path of movement of theflexible beam as the flexible beam is moved between its retracted andadvanced positions to maintain the predetermined distance of movement ofthe clamp member within the tool assembly constant in thenon-articulated and articulated positions of the tool assembly, whereinthe first pivot link includes a convex guide surface that is engagedwith the first side of the flexible drive beam when the tool assembly isin the non-articulated position to define a deformed portion in theflexible drive beam.
 7. The reload assembly of claim 6, wherein thesecond pivot link includes a concave guide surface that faces the secondside of the flexible drive beam.